GNOME’s Adwaita Theme is really great. But we can easily make it greater. So if you want to make some slightly changes, or to create a new theme from scratch this is how to.

Issues With GTK Themes

There are some issues with how GNOME GTK Theming works.

Placement

For system-wide installation, you just need to copy your theme under:

/usr/share/themes

For user-specif installations you need to copy the GTK3

~/.local/share/themes

and GTK2 variant in

~/.themes

Annoying bug..

CSS Properties & Pseudo-Classes

GTK’s CSS isn’t standards-compliant with CSS standards. It is more or less a set of CSS, with some additional or missing features. Documentation is also missing and you need to check on how Adwaita does it to find all the available properties.